I present new estimates of the elasticity of substitution between capital and labor using data from the private sector of the U.S. economy for the period 1948-1998. I first adopt Berndt's (1976) specification, which assumes that technological change is Hicks neutral. Consistently with his results, I estimate elasticities of substitution that are not significantly different from one. I next show, however, that restricting the analysis to Hicks-neutral technological change necessarily biases the estimates of the elasticity towards one. When I modify the econometric specification to allow for biased technical change, I obtain significantly lower estimates of the elasticity of substitution. I conclude that the U.S. economy is not well described by a Cobb-Douglas aggregate production function. I present estimates based on both classical regression analysis and time series analysis. In the process, I deal with issues related to the nonsphericality of the disturbances, the endogeneity of the regressors, and the nonstationarity of the series involved in the estimation.
We present a North-South model of international trade in which differentiated products are developed in the North. Sectors are populated by ﬁnal-good producers who differ in productivity levels. On the basis of productivity and sectoral characteristics, ﬁrms decide whether to integrate into the production of intermediate inputs or outsource them. In either case they have to decide from which country to source the inputs. Final-good producers and their suppliers must make relationship-speciﬁc investments, both in an integrated ﬁrm and in an arm’s-length relationship. We describe an equilibrium in which ﬁrms with different productivity levels choose different ownership structures and supplier locations. We then study the effects of within-sectoral heterogeneity and variations in industry characteristics on the relative prevalence of these organizational forms.